This application incorporates by reference the following copending applications.
1. Targets Ser. No. 348,803 now U.S. Pat. No. 4,654,949 PA0 2. Robot Calibration Ser. No. 453,910 now U.S. Pat. No. 4,753,569 PA0 3. Pulsed Robotic Inspection now U.S. Pat. No. 4,585,350 PA0 4. Pulsed Robotic Inspection CIP Ser. No. 779,457 filed Sept. 24, 1985.
Copending applications by the inventor have discussed target based guidance concepts for robot in machinery control which can lead to higher accuracy, lower cost, higher speed and other desirable solutions in a reliable, accurate manner capable of widespread application.
This disclosure extends this idea toward specific problems related to the manufacture of car bodies, aircraft structures, covering and both the assembly of the components and the fixtures that assist in this assembly.
One embodiment of the invention aids in manufacture of fixtures. Quite clearly, the construction of high precision fixtures for either assembly fixtures, weld fixtures or check fixtures required by today's manufacturer of aircraft and automobiles is an extremely expensive and time consuming proposition. It is estimated for example that within a large automobile manufacturer in North America, at least $2 Billion in such fixtures at any one time are circulating. When new car lines come out the fixtures for the previous line become scrap.
What's worse, the fixture costs generally have a long time delay in their delivery. Since this is an area where numerous engineering changes occur during the engineering of the car, widespread last minute changes in the fixtures are required which causes enormous cost escalations plus further adds to the delays in getting the car lines to the market which can lead to significant lost market share consequences.
What is disclosed herein is a novel target based technique to assist in the construction of fixtures in either a manual or an automatic manner, greatly reducing the cost and the delivery time.
A particular area of interest is the disclosure of target based equipment which can aid an operator or a robot in the positioning of check, locating or other actual assembly details onto the fixtures as well as the linking of such data to the CAD data systems for the part and/or fixture.
Fixtures constitute a large percentage of the cost of tooling for new body styles and their construction interjects into any new model program a considerable time delay. Computer aided automatic vision based metrology systems can be utilized to materially speed up this effort to both reduce costs and quicken the delivery time of such fixturing.
Besides the obvious increased cost effectiveness, the system proposed has two other major advantages. First, it is directly interfaceable to CAD systems and therefore totally ameanable with future thrusts in math model car design and build.
The second thing, is that the real time nature of the data provided allows the system to first be utilized in a manual mode, upward to semi automatic and then finally to full robot fixtureless assembly using the same basic concepts founded on metrological principles.
This proposal is generally related in some aspects to the procedure of laying out large fabricated fixtures and other objects using theodolites. Such theodolites which currently have become digitized with reliable programming allow a considerable simplification of the layout procedure and can materially aid in the checkout of fixtures and other structures.
However, the use of such theodolites does very little for the person actually charged with constructing the fixture. What is proposed here however is a dynamic interactive target based system used by itself or in conjunction with theodolites which actually allow fabrication of the object itself taking data concerning the part for which the fixture is to fit, such as a body side or what have you from the CAD data base and feeding to a sensor unit that is capable of seeing the detail to be assembled and possibly the part such as a framework or other detail to which it is to be mated.
In the first case, this allows an operator to position the detail in computer defined space, rapidly and easily from which it would then be locked down via welding, lock screws or what have you. In addition, the process provides an automatic check, again relative to computer data space for the fixture using the part data master. In short, this is an entirely CAD compatible manufacturing process which can start out manually--a big advantage.
In future applications, the process can be further automated with robots handling one or more of the positioning, welding, or attaching tasks. It is not all far removed to consider that fixtures themselves could be robot constructed.
The step beyond that is to eliminate fixtures entirely using the robots to essentially form the fixture in a sequential mode. However, this is not thought to be generally applicable but certainly could be applicable on certain sub assemblies, details or the like. The beauty of this whole idea is that it can start simply off-line in the fixture build and in the end turns out to what may be the key to the whole line itself, all the while saving large sums of money and time.
The process is not necessarily limited solely to the fabrication of fixtures. Other conveyor details including nesting fixtures, possibly even dies and molds could fit this as well.